1. Field of the Invention
The present invention relates to a vehicular air conditioning apparatus mounted in a vehicle for blowing air into a vehicle compartment that has been adjusted in temperature by a cooling means or a heating means, for thereby adjusting temperature of the vehicle compartment.
2. Description of the Related Art
In a vehicular air conditioning apparatus that is mounted in a vehicle, internal and external air is introduced into a casing by a blower, and after cooled air, which has been cooled by an evaporator that forms a cooling means, and heated air, which has been heated by a heater core that forms a heating means, are mixed together in the casing at a predetermined mixing ratio, the mixed air is blown out from a defroster blow-out port, a face blow-out port, or a foot blow-out port, whereby adjustment of temperature and humidity in the vehicle compartment is carried out.
With this type of vehicular air conditioning apparatus, for example, it is known to provide a first blower for the purpose of introducing vehicle compartment air into the casing, and a second blower for the purpose of introducing external air outside of the vehicle compartment into the casing. In such a vehicular air conditioning apparatus, air that is introduced from an internal air introduction port by rotation of the first blower is heated by a first heat exchanger and then is blown into the vehicle compartment through a first air passage from the face blow-out port or the foot blow-out port. In addition, air that is introduced from an external air introduction port by rotation of the second blower is heated by a second heat exchanger and then is blown into the vehicle compartment through a second air passage from the defroster blow-out port. More specifically, a switching operation is performed such that when air is blown out from the face blow-out port or the foot blow-out port, the first blower is driven and air from the interior of the vehicle is introduced, whereas when air is blown out from the defroster blow-out port, the second blower is rotated and external air is introduced.
Further, using separate air conditioning devices having first and second blowers for introducing air, the first blower is arranged facing toward an external air introducing port of a duct, and the second blower is arranged facing toward an interior air introducing port. Additionally, the first blower includes a switching means, which is capable of switching the air that is introduced to the duct by the first blower between interior air and exterior air. In addition, the air that is introduced to the duct by the first blower is switched between interior air and exterior air by the switching means, and after the air has been adjusted in temperature by a heating means and a cooling means so as to provide a desired temperature together with the air introduced to the duct by the second blower, the air is blown into a desired region in the vehicle compartment through a face blow-out port, a foot blow-out port, or a defroster blow-out port. (See, for example, Japanese Laid-Open Patent Publication No. 05-178068, Japanese Laid-Open Patent Publication No. 06-040236, and Japanese Laid-Open Patent Publication No. 06-191257.)
When air, which is separately adjusted in temperature, is blown to the respective seats of the passengers as in the vehicular air conditioning apparatus disclosed in Japanese Laid-Open Patent Publication No. 05-178068, Japanese Laid-Open Patent Publication No. 06-040236, and Japanese Laid-Open Patent Publication No. 06-191257, the passages for flowing air in the air conditioning apparatus need to have a complicated structure. Further, it is necessary to provide dampers in the passages for opening/closing or changing the flowing direction of air in the passages. For the passages in the casing, however, it is impossible to form rotatable dampers integrally, by resin molding, metal casting or the like.
Also, in the vehicular air conditioning apparatus, it is not easy to carry out maintenance and management of air passages or components therein, since the apparatus itself comprises an integrally-formed casing and thus the apparatus has a complicated structure. In particular, maintenance and management of the dampers are difficult due to frequent rotation thereof, which perform strict temperature control all the time.